The present invention is directed toward an apparatus for spraying refractory lining and more particularly toward an apparatus which is adapted to be suspended into the interior of a ladle and which uses a first pair of nozzles to coat the bottom of the ladle and thereafter uses a second pair of nozzles to coat the side walls of the ladle.
In the iron and steel industry, deep walled refractory bodies such as ladles, soaking pits and furnaces are subjected to extremely high temperatures over long periods of time. These high temperatures cause deterioration of the refractory linings of the bodies. After the lining has deteriorated to a certain point, the lining must be replaced or repaired before the ladle, etc. can be further used.
The interior surface of the ladles can be repaired in a number of different ways. One common repair which has come into common practice is to spray a protective coating of refractory material onto the interior of the ladle.
Refractory spraying apparatus for ladles and the like which has been in common use are hand operated devices. With these, a workman is required to enter the ladle and to hand spray the refractory material about the interior. Hand spraying of the ladles is an extremely time consuming job. Additionally, the quality of the job accomplished is only as good as the skill of the laborer.
A further problem encountered in hand spraying of ladles is the cooling time required before a workman can enter the ladle or furnace. For example, a ladle of ordinary and common size which has just been taken out of use will require between six to twelve hours to cool before a workman can enter the ladle to spray a new lining. The turn around time between cooling, spraying and drying of a ladle can be extremely detrimental to production rates in a steel mill as well as being costly.
There has, for some time, been a requirement in the industry for a ladle spraying apparatus which will operate automatically to deposit the lining in a controlled manner and also one which can spray the lining on immediately or shortly after the ladle is taken out of service without having to wait for the ladle to cool and be hand sprayed.
One refractory spraying apparatus which has been in use and which has overcome substantially all of the problems of the previous hand-held devices is described in U.S. Pat. No. 3,797,745. This patent includes a pair of nozzles mounted at the lower end of a conduit which is suspended into the interior of a ladle. The conduit is actually a pair of concentric conduits so that the dry refractory material and water could be brought down through the interior of the conduits thus allowing a nozzle to continuously rotate in one direction. The internal conduit carrying the water, however, had a tendency to wear excessively due to the passage of the refractory material over its outer surface. In addition, with only two nozzles, it was difficult to spray the bottom surface of the ladle.